JP2008026609A - Laser optical apparatus and method for controlling operation of actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser optical apparatus capable of maintaining high performance. <P>SOLUTION: The laser optical apparatus includes: a laser beam emitting part for emitting a laser beam; a laser beam receiving part for receiving the laser beam emitted by the laser beam emitting part; a converging optical unit 3 for guiding the laser beam emitted from the laser beam emitting part to the laser beam receiving part; actuators 8, 9 for transferring the converging optical unit; an intensity detector for detecting the intensity of the laser beam introduced to the laser beam receiving part; and a controller 7 which, on the basis of the laser beam intensity detected by the intensity detector, controls the operation of the actuators in the manner that the laser beam guided by the converging optical unit is radiated to the center in the incident face of the laser beam receiving part. The actuators includes a piezoelectric element and a vibrator, wherein, with micro vibration generated by the excitation of the piezoelectric element, the vibrator comes in contact with the converging optical unit in the manner actuating frictional force directly or indirectly thereon. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for controlling the operation of a laser optical device and an actuator, and in particular, controls the operation of a laser optical device and an actuator that perform control so that laser light is directed toward the center of an incident surface of an optical fiber that is a laser receiving unit. On how to do.

  A laser optical device transmits laser light emitted by a semiconductor laser (hereinafter referred to as LD) and modulated by information to an optical fiber, and laser light emitted from the optical fiber is transmitted to another optical fiber. And is composed of an optical component such as a condensing lens for condensing laser light from an LD, an LD, or an optical fiber, and an optical fiber.

  In such a laser optical device, an LD, a condensing lens, etc. must be positioned with high accuracy with respect to an optical fiber having a core diameter of several μm. Usually, these optical components use welding or an adhesive. Fixed firmly.

  However, even if the laser optical apparatus is configured by positioning and fixing the mutual positions of the parts with an adhesive in this way, the following problems remain. First, when a laser optical device is manufactured in this way, the quality of a product can only be determined after being bonded and dried. In addition, it is considered relatively difficult to achieve a high yield with such a laser optical device. Second, it is impossible to correct the performance when there is a change over time. Third, there is a possibility that the fixed position may be shifted due to a temperature change. In particular, when the laser light source is in the vicinity of the optical component, the influence of self-heating of the laser light source is significant.

  Therefore, a configuration of a laser optical device capable of maintaining high performance without being affected by environmental changes including changes in mechanical conditions such as vibration, changes in ambient temperature, changes with time, and the like has been desired and variously studied.

For example, an optical deflector including a condensing lens that condenses laser light from a laser light source toward an optical fiber, and an actuator that moves the condensing lens so that the laser light travels toward the core center of the optical fiber. Means, a photodetector for detecting the intensity of the laser light guided into the optical fiber, and a light beam so that the position of the laser light deflected by the optical deflecting means in the plane of incidence on the optical fiber is directed toward the center of the core. And a control means for performing negative feedback control on the deflecting means. The control means detects light while causing the laser light to vibrate slightly with a constant period and a constant amplitude in the X or Y direction. The detector detects the intensity change of the laser beam, and based on the result, grasps the deviation of the laser beam from the core center in the optical fiber incident surface and directs the laser beam to the core center. Controlled so that the optical communication device technology (see Patent Document 1) is known.
JP 2003-338895 A

  By the way, in order to perform control so that the laser beam is directed toward the center of the incident surface of the optical fiber, an actuator capable of submicron order resolution and highly accurate position control is required.

  However, the optical communication device disclosed in Patent Document 1 does not have such an actuator capable of high-resolution and high-precision position control, and it is difficult to perform submicron-order position control. it is conceivable that. Further, the condenser lens is moved by an actuator driven by a sine wave signal, and a change in the intensity of the laser light is detected by the photodetector while the condenser lens is moving, that is, during wobbling. Therefore, the S / N ratio is lowered, and it is difficult to detect the intensity change of the laser beam with high accuracy.

  The present invention has been made in view of the above problems, and a laser optical device capable of maintaining high performance at all times in a laser optical device that performs control so that laser light is directed toward the center of the optical fiber incident surface. The purpose is to provide.

  The above object is achieved by the invention described in any one of 1 to 9 below.

1. A laser beam emitting section for emitting a laser beam;
A laser beam receiving unit that receives the laser beam emitted from the laser beam emitting unit;
A condensing optical unit for guiding laser light emitted from the laser light emitting unit to the laser light receiving unit;
An actuator for moving the condensing optical unit;
An intensity detector for detecting the intensity of the laser beam introduced into the laser beam receiver;
A control unit that controls the operation of the actuator so that the laser beam guided by the condensing optical unit is directed to the center of the incident surface of the laser beam receiving unit based on the intensity of the laser beam detected by the intensity detecting unit. In a laser optical device having:
The actuator includes a piezoelectric element and a vibrating body that generates minute vibrations by excitation of the piezoelectric element and is in contact with the condensing optical unit so that a frictional force acts directly or indirectly. A laser optical device.

  2. 2. The laser optical device according to 1, wherein the intensity of the laser beam detected by the intensity detection unit is acquired by the control unit while the actuator stops driving.

  3. 3. The laser optical device according to 1 or 2, wherein the actuator is driven by a pulse signal from the control unit.

4). The condensing optical unit includes a refractive optical element having power arranged on the optical axis of the laser light emitted from the laser light emitting unit,
4. The laser optical device according to any one of claims 1 to 3, wherein the actuator moves the condensing optical unit along a plane substantially perpendicular to the optical axis of the laser light.

5. The condensing optical unit is arranged on the optical axis of the laser light emitted from the laser light emitting unit and focuses on the point intersecting with the optical axis of the laser light emitted from the laser light emitting unit. A reflective optical element having a power fixed to be slidable integrally with the optical unit;
4. The laser optical device according to claim 1, wherein the actuator swings the condensing optical unit around a point where the laser light intersects the reflection optical element. 5.

  6). The actuator includes a first wobbling operation in which the control unit periodically moves the condensing optical unit in a first movement direction at a predetermined frequency, and a second movement orthogonal to the first movement direction. 6. The laser optical device according to any one of 1 to 5, wherein a second wobbling operation that is periodically moved in a direction at a predetermined frequency is alternately executed.

7). When the frequency of the first wobbling operation described in 6 is f1 and the frequency of the second wobbling operation is f2, f1 and f2 satisfy the relationship of (Equation 1) or (Equation 2) below,
The laser optical apparatus according to any one of 1 to 5, wherein the actuator performs the first wobbling operation and the second wobbling operation simultaneously by the control unit.
f1 = 2 × n × f2 (Formula 1)
f2 = 2 × n × f1 (Formula 2)
(In the formula, n is a positive integer.)
8). By moving the condensing optical unit that guides the laser beam to the laser beam receiving unit using the actuator, the laser beam emitted from the laser beam emitting unit is directed toward the center of the incident surface of the laser beam receiving unit. In a method for controlling the operation of an actuator,
The actuator includes a piezoelectric element and a vibrating body that generates minute vibrations by excitation of the piezoelectric element and is in contact with the condensing optical unit so that a frictional force acts directly or indirectly.
A detection step of detecting the intensity of the laser beam introduced into the laser beam receiving unit while the actuator is stopped driving;
Performing a first wobbling operation for periodically moving the condensing optical unit at a predetermined frequency in the first movement direction based on the intensity of the laser light detected in the detection step;
An operation of the actuator, wherein the actuator is alternately executed with a step of performing a second wobbling operation of periodically moving at a predetermined frequency in a second movement direction orthogonal to the first movement direction. How to control.

9. When the frequency of the first wobbling operation described in the above 8 is f1, and the frequency of the second wobbling operation is f2, f1 and f2 satisfy the relationship of the following (Equation 1) or (Equation 2):
9. A method for controlling operation of an actuator, wherein the step of performing the first wobbling operation and the step of performing the second wobbling operation are simultaneously performed by the actuator according to the item 8.
f1 = 2 × n × f2 (Formula 1)
f2 = 2 × n × f1 (Formula 2)
(In the formula, n is a positive integer.)

  According to the present invention, an actuator that generates minute vibrations by excitation of a piezoelectric element and moves the condensing optical unit by a vibrating body that is in contact with the condensing optical unit so that a frictional force acts directly or indirectly is used. Thus, the laser light guided by the condensing optical unit is controlled so as to be directed toward the center in the incident surface of the laser light receiving unit. That is, since the condensing optical unit is moved by a vibrating body capable of performing minute vibrations, position control on the order of submicrons can be performed with high resolution and high accuracy, and high performance can always be maintained.

  Further, since the actuator moves the condensing optical unit by a frictional force, the condensing optical unit can maintain the posture while the energization to the actuator is stopped and the driving is stopped. That is, the position of the laser beam guided by the condensing optical unit on the incident surface of the laser beam receiving unit can be fixed. Therefore, by acquiring the intensity of the laser beam detected by the intensity detector during this period, it is possible to acquire a stable intensity of the laser beam with high accuracy.

  The control unit drives the actuator with a pulse signal. Therefore, since step driving can be performed, position control can be performed with high accuracy.

  The condensing optical unit is provided with a refractive optical element or a reflective optical element. Therefore, it is possible to easily change the position of the laser beam on the incident surface of the laser beam receiving unit without complicating the apparatus.

  In addition, the control unit alternately executes the first wobbling operation and the second wobbling operation. Therefore, for example, while the first wobbling operation is being performed, the position of the laser beam in the second direction within the incident surface to the laser beam receiving unit is held, and thus the second direction of the laser beam. The position control of the laser beam in the first direction can be performed with high accuracy without the intensity of the laser beam changing due to the position change at.

Further, when the frequency of the first wobbling operation is f1 and the frequency of the second wobbling operation is f2, f1 and f2 satisfy the relationship of (Equation 1) or (Equation 2) below, and the control unit The first wobbling operation mode and the second wobbling operation mode are executed simultaneously.
f1 = 2 × n × f2 (Formula 1)
f2 = 2 × n × f1 (Formula 2)
(In the formula, n is a positive integer.)
Thus, for example, when the frequency f1 of the first wobbling operation is an even multiple of the frequency f2 of the second wobbling operation, the laser light reception of the laser light is performed during the execution of the first wobbling operation. Since the position in the second direction within the plane of incidence on the part is held, the intensity of the laser beam does not fluctuate due to the position change in the second direction of the laser beam. Therefore, the position control of the laser beam in the first direction can be performed with high accuracy without being affected by the second wobbling operation. As a result, the first wobbling operation and the second wobbling operation can be performed simultaneously, and the wobbling operation can be speeded up.

  Embodiments of a laser optical device according to the present invention will be described below with reference to the drawings.

[Embodiment 1]
First, the configuration of the laser optical device 1 according to the first embodiment will be described with reference to FIG. FIG. 1 is a diagram showing an outline of the overall configuration of the laser optical device 1.

  As shown in FIG. 1, the laser optical device 1 includes optical fibers 21 and 22, a condensing optical unit 3, collimator lenses 41 and 42, a half mirror 5, a photodiode 6, a control unit 7, and actuators 8 and 9. Have.

  The optical fibers 21 and 22, the condensing optical unit 3, and the collimator lenses 41 and 42 are arranged on a common optical axis, and the laser light emitted from the optical fiber 21 is incident on the incident surface of the optical fiber 22 by the condensing optical unit 3. It is condensed toward 22a. As described above, the optical fibers 21 and 22 function as a laser beam emitting unit and a laser beam receiving unit in the laser optical device according to the present invention, respectively. Note that an LD may be used instead of the optical fiber 21 as the laser light emitting portion, and an optical waveguide or the like may be used instead of the optical fiber 22 as the laser light receiving portion.

  The half mirror 5 reflects a part of the laser beam emitted from the emission surface 22 b of the optical fiber 22 and guides it to the photodiode 6.

  The photodiode 6 corresponds to an intensity detector in the present invention, and detects the intensity of the laser beam guided by the half mirror 5 and converts it into an electric signal.

  The control unit 7 changes the position of the condensing optical unit 3 via the actuators 8 and 9 based on the intensity of the laser light detected by the photodiode 6, and the laser light guided by the condensing optical unit 3 is light. The operation of the actuators 8 and 9 is controlled so as to be directed toward the center in the incident surface 22a of the fiber 22. Details of the control of the actuators 8 and 9 by the control unit will be described later.

  The actuators 8 and 9 include a later-described laminated or roll-type piezoelectric element 811, which generates minute vibrations by excitation of the piezoelectric element 811. The driving shaft 812 corresponding to the vibrating body in the present invention is connected to the condensing optical unit 3. The condensing optical unit 3 is moved by frictional force. The actuator 8 can move the condensing optical unit 3 in one axial direction (X-axis direction) in a plane perpendicular to the optical axis, while the actuator 9 allows the condensing optical unit 3 to move It can be moved in the Y-axis direction orthogonal to the X-axis direction in a plane perpendicular to the optical axis. The configuration of the actuators 8 and 9 will be described later.

  Next, the configuration of the condensing optical unit 3 and the arrangement of the actuators 8 and 9 will be described with reference to FIG. FIG. 2 is a configuration diagram of an XY stage including the condensing optical unit 3 and the actuators 8 and 9.

  As shown in FIG. 2, the condensing optical unit 3 includes a condensing lens 301 corresponding to the refractive optical element in the present invention, a lens holder 302 for holding the condensing lens 301, and the like. Is supported to be movable in the direction and the Y-axis direction.

  Next, the configuration of the actuators 8 and 9 will be described with reference to FIG. 3A is a configuration diagram of a truss type actuator provided with a laminated piezoelectric element, FIG. 3B is a configuration diagram of a SIDM type actuator provided with a roll type piezoelectric element, and FIG. 3C is a roll diagram. It is a block diagram of the LVA type actuator provided with the type piezoelectric element. Truss type actuators, SIDM type actuators, and LVA type actuators are all known actuators including a vibrating body that generates minute vibrations by excitation of a piezoelectric element. In the embodiment of the laser optical apparatus according to the present invention, any actuator provided with such a vibrating body may be used. Here, an outline of the configuration of the SIDM actuator will be described. Details of the SIDM type actuator are disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-185055 “Piezoelectric Conversion Element” and the like, and detailed description thereof is omitted here. In addition, the configuration of the actuator 9 is the same as that of the actuator 8, and the description thereof is omitted.

  As shown in FIG. 3B, the SIDM actuator 8 includes a piezoelectric element 811, a drive shaft 812, a weight 813, a moving body 814, and the like. The piezoelectric element 811 that is an electro-mechanical energy conversion element has a control unit. 7 to input a drive signal to generate minute vibrations and to vibrate the drive shaft 812 in the direction of arrow A, so that the drive shaft 812 is pressed against the movable body 814 in a pressurized state by a frictional force. It generates movement. Here, the lens holder 302 corresponds to the moving body 82.

  Next, the electric circuit configuration of the laser optical device 1 will be described with reference to FIG. FIG. 4 is an electric circuit block diagram of the laser optical device 1.

  The main electric circuit block of the laser optical device 1 includes an analog signal processing circuit 10, a control unit 7, and the like.

  The analog signal processing circuit 10 converts the current signal detected by the photodiode 6 and converted according to the intensity of the laser light into a voltage signal.

  The control unit 7 includes a low-pass filter 71, an A / D converter 721, an alignment controller 723, a control CPU 72 including an X-PWM 724, a Y-PWM 725, and a drive circuit 73 including an X-amplifier 731, a Y-amplifier 732, and the like. Consists of

  The low pass filter 71 removes high frequency noise superimposed on the voltage signal output from the analog signal processing circuit 10.

  The A / D converter 721 converts the voltage signal output from the low pass filter 71 into a digital signal.

  The alignment controller 723 performs rectangular wave phase detection on the digital signal sampled by the A / D converter 721, and based on the result of the rectangular wave phase detection, 3 of the drive signal (drive pulse) for driving the actuators 8 and 9 is obtained. Two parameters are set: drive frequency, duty ratio, and number of pulses. Details of the rectangular wave phase detection and parameter setting operation performed by the alignment controller 723 will be described later.

  X-PWM 724 and Y-PWM 725 generate drive pulses for driving actuators 8 and 9 in the X-axis direction and Y-axis direction, respectively, based on the three parameters set by alignment controller 723.

  Here, the parameter setting operation performed by the alignment controller 723 and the operations of the X-PWM 724 and the Y-PWM 725 will be described with reference to FIG. FIG. 6A is a diagram showing three parameters, FIG. 6B is a time chart showing drive pulses at the time of forward movement generated based on the set three parameters, and FIG. It is a time chart which shows the drive pulse at the time of reverse produced | generated based on the set three parameters.

  The alignment controller 723 includes a time counter that measures a time (not shown), and sets a threshold TC3 of the time counter based on the digital signal sampled by the A / D converter 721. As shown in FIG. 6A, the time counter is reset at a set threshold value TC3 and repeats the time measurement again. As a result, the timer count waveform exhibits a triangular wave, and the frequency of this triangular wave becomes the frequency of the drive pulse. Next, the alignment controller 723 sets the thresholds TC1 and TC2 of the time counter based on the digital signal sampled by the A / D converter 721. With these threshold values TC1 and TC2, the ON time of the driving pulse at the time of forward movement and the backward movement, that is, the duty ratio is set. Similarly, the alignment controller 723 sets the time ttwc of the time counter based on the digital signal sampled by the A / D converter 721. As a result, the number of drive pulses is set.

  When the threshold values TC3, TC1, TC2, and twc are set by the alignment controller 723 in this manner, the X-PWM 724 and Y-PWM 725 are set to the threshold values TC3, TC1 as shown in FIGS. , TC2, and twc, the drive pulses φPWM1 and φPWM2 at the time of forward and reverse are generated at the drive frequency, duty ratio, and number of pulses. FIGS. 6A to 6C are time charts when the set number of pulses is three.

  Returning to FIG. 4, each of the X-amplifier 731 and the Y-amplifier 732 includes the well-known H bridge circuit shown in FIG. 5, amplifies the drive pulses generated by the X-PWM 724 and Y-PWM 725, and 9 is driven.

  In the laser optical device 1 having such a configuration, the control unit 7 detects the intensity of the laser light detected by the photodiode 6, that is, the digital signal sampled by the A / D converter 721, and detects the rectangular wave phase. Based on the result of wave phase detection, the values of three parameters of drive pulses for driving the actuators 8 and 9 are set. Then, the controller 7 drives the actuators 8 and 9 with drive pulses based on the set three parameters, changes the position of the condensing optical unit 3, and the laser light guided by the condensing optical unit 3 is the optical fiber 22. To be directed toward the center of the incident surface 22a. Such a series of operations is hereinafter referred to as “wobbling”.

  Here, the rectangular wave phase detection operation performed by the control unit 7 will be described with reference to FIG. FIG. 7A is a profile in the X-axis direction of the laser light projected on the incident surface 22a to the optical fiber 22, and FIG. 7B is a schematic diagram showing a rectangular wave phase detection operation. The rectangular wave phase detection operation in the Y-axis direction is the same as that in the X-axis direction and will not be described.

For example, as shown in FIG. 7A, the position of the laser beam guided by the condensing optical unit 3 in the incident surface 22a to the optical fiber 22 is X0, and is detected by the photodiode 6 at that time. When the intensity of the laser beam is P0, rectangular wave phase detection is started.
Here, the amplitude of the rectangular wave phase detection is assumed to be two pulses by the drive pulses φPWM1 and φPWM2 shown in FIG.

  First, it stops by moving two pulses in the positive direction. At this time, the position of the laser beam moves from X0 to X1, and the intensity of the laser beam varies from P0 to P1. The A / D converter 721 samples the laser light intensity P1 for a predetermined time, and the alignment controller 723 integrates the sampled laser light intensity P1. The intensity of the integrated laser beam is shown as PI1 in FIG. Next, it moves 4 pulses in the negative direction and stops. At this time, the position of the laser beam moves from X1 to X2, and the intensity of the laser beam varies from P1 to P2. The A / D converter 721 samples the intensity P2 of the laser beam for a predetermined time, and the alignment controller 723 integrates the intensity P2 of the sampled laser beam. The intensity of the integrated laser beam is shown as PI2 in FIG. Next, it moves 2 pulses in the positive direction and stops. Then, the difference between the integrated values PI1 and PI2 obtained at each position is obtained. The difference is shown as ΔPI in FIG. The difference ΔPI obtained in this way is hereinafter referred to as “rectangular wave phase detection output”.

  Here, the rectangular wave phase detection output ΔPI will be described with reference to FIG. 8A shows a profile in the X-axis direction of the laser light projected onto the incident surface 22a of the optical fiber 22, and FIG. 8B shows a rectangular wave phase detection corresponding to the profile shown in FIG. 8A. It is a schematic diagram which shows output (DELTA) PI. As shown in FIG. 8B, the rectangular wave phase detection output ΔPI is 0 at the position where the intensity of the laser beam is maximized, and takes positive and negative values at the left and right of the position where the intensity of the laser beam is maximized.

  Returning to FIG. 7, the rectangular wave phase detection output ΔPI obtained in this way is multiplied by a coefficient (gain) set in advance to obtain a correction amount (correction pulse number), and the calculated correction pulse number. Move. Such operations are repeated so that the rectangular wave phase detection output ΔPI is controlled to approach zero. That is, the laser light guided by the condensing optical unit 3 is controlled so as to be directed toward the center in the incident surface 22 a of the optical fiber 22.

  Next, the flow of the wobbling operation will be described with reference to FIG. 9 and FIG. FIG. 9 is a flowchart showing the flow of the wobbling operation. FIG. 10 is a time chart of the wobbling operation.

  First, the wobbling operation in the X-axis direction is executed. First, the alignment controller 723 sets the number of drive pulses (for example, 2 pulses) in the positive direction (forward direction) for performing the wobbling operation in the period tw1 shown in FIG. The optical unit 3 is moved by two pulses in the positive direction of the X axis (step S1). When the condensing optical unit 3 stops moving and the position of the laser beam on the optical fiber 22 in the incident surface 22a is stabilized, the A / D converter 721 starts sampling (step S2), and the alignment controller 723 Then, the intensity of the laser beam sampled by the A / D converter 721 in the period tw2 is integrated to obtain an integrated value PI1 (step S3). Next, the alignment controller 723 sets the number of drive pulses (for example, 4 pulses) in the negative direction (backward direction) in the period tw3, and causes the condensing optical unit 3 to move 4 pulses in the negative direction of the X axis via the actuator 8. Move by one minute (step S4). When the condensing optical unit 3 stops moving and the position of the laser light in the incident surface 22a on the optical fiber 22 is stabilized, the A / D converter 721 starts sampling in the same manner as in steps S2 and S3. Then (step S5), the alignment controller 723 integrates the intensity of the laser light sampled by the A / D converter 721 in the period tw4, and obtains an integral value PI2 (step S6). Then, the alignment controller 723 sets the number of drive pulses (for example, 2 pulses) in the positive direction (forward direction) in the period tw5, and moves the condensing optical unit 3 by two pulses in the positive direction of the X axis via the actuator 8. Move (step S7).

  In step 4, when the condensing optical unit 3 is moved by 4 pulses in the negative direction (retreat direction) of the X axis, in order to suppress the variation in the drive amount for each pulse during the transition of the rise of the actuator 8. First, it is driven with two pulses, and after stopping once, the remaining two pulses are driven.

  In this way, when the integral values PI1 and PI2 are acquired, the alignment controller 723 subtracts PI2 from the integral value PI1 in the period tw6 to obtain a difference ΔPI (step S8), and whether or not the value of the difference ΔPI is positive. Is determined (step S9). When the value of the difference ΔPI is positive (step S9; Yes), the position where the intensity of the laser light projected onto the incident surface 22a to the optical fiber 22 is maximum is further in the positive direction (forward direction). The controller 723 obtains a correction amount (correction pulse number) in the forward direction (forward direction) by multiplying the difference ΔPI by a coefficient (gain) set in advance in the period tw7, and passes the actuator 8 with the obtained correction pulse number. Then, the condensing optical unit 3 is moved by the correction pulse in the positive direction of the X axis (step S10). On the other hand, when the value of the difference ΔPI is negative in step S9 (step S9; No), the position where the intensity of the laser beam projected onto the incident surface 22a to the optical fiber 22 is maximized is in the negative direction (backward direction). Therefore, the alignment controller 723 calculates the correction amount (correction pulse number) in the negative direction (reverse direction) in the same manner as in step S10, and moves the condensing optical unit 3 via the actuator 8 with the calculated correction pulse number. The correction pulse is moved in the negative direction of the X axis (step S11).

  In this way, when one cycle of the wobbling operation in the X-axis direction is completed in the period twX, the wobbling operation in the Y-axis direction is then performed in the period twY shown in FIG. 10B in the same manner as in steps S1 to S11. One cycle is executed (step S12). Then, the difference ΔPI is 0, that is, the laser beam guided by the condensing optical unit 3 is transmitted through the optical fiber 22 by sequentially and repeatedly executing such an x-axis wobbling operation and a y-axis wobbling operation. It can be made to go to the center in the entrance plane 22a.

  As described above, in the laser optical device 1 according to the present invention, a minute vibration is generated by the excitation of the piezoelectric element 811, and the drive shaft is in contact with the condensing optical unit 3 so that a frictional force acts directly or indirectly. Using the actuators 8 and 9 that move the condensing optical unit 3 by 812, the laser light guided by the condensing optical unit 3 is controlled so as to go to the center in the incident surface 22 a of the optical fiber 22. That is, since the condensing optical unit 3 is moved by the drive shaft 812 capable of performing minute vibrations, the position of the sub-micro order can be controlled with high resolution and high accuracy, and high performance can always be maintained. it can.

  Further, since the actuators 8 and 9 move the condensing optical unit 3 by a frictional force, the condensing optical unit 3 can maintain the posture while the energization to the actuators 8 and 9 is stopped and the driving is stopped. it can. That is, the position of the laser beam guided by the condensing optical unit 3 in the incident surface 22a to the optical fiber 22 can be fixed. Therefore, by acquiring the intensity of the laser beam detected by the photodiode 6 during this period, the stable intensity of the laser beam can be acquired with high accuracy. Thereby, the S / N ratio of the rectangular wave phase detection can be improved.

  The actuators 8 and 9 are driven by pulse signals. Therefore, rectangular wave phase detection can be performed with high accuracy.

  In addition, the wobbling operation in the X-axis direction and the wobbling operation in the Y-axis direction are switched alternately and sequentially. Therefore, for example, while the wobbling operation in the X-axis direction is being executed, the position of the laser light in the incident surface 22a on the optical fiber 22 in the Y-axis direction is held, so that the laser light in the Y-axis direction is held. The intensity of the laser beam does not fluctuate due to the position change, and the position control of the laser beam in the X-axis direction can be performed with high accuracy.

[Embodiment 2]
Next, the laser optical device 1 according to the second embodiment will be described. Since the main configuration is substantially the same as that of the first embodiment, detailed description is omitted, and the timing of the wobbling operation in the X-axis direction and the dithering operation in the Y-axis direction, which are different from the first embodiment, will be described. .

  In the laser optical device 1 according to the first embodiment, the wobbling operation in the X-axis direction and the wobbling operation in the Y-axis direction are switched alternately and repeatedly, but the laser optical device 1 according to the second embodiment is The frequency of the wobbling operation in the axial direction and the frequency of the wobbling operation in the Y-axis direction are set so as to satisfy a predetermined relationship and are executed simultaneously.

  Specifically, this will be described with reference to FIG. FIG. 11 is a time chart of the wobbling operation according to the second embodiment.

Here, when the frequency of the wobbling operation in the X-axis direction is f1, and the frequency of the wobbling operation in the Y-axis direction is f2, f1 and f2 are set to values satisfying the relationship of the following (Expression 1) or (Expression 2). To do.
f1 = 2 × n × f2 (Formula 1)
f2 = 2 × n × f1 (Formula 2)
(In the formula, n is a positive integer.)
Thus, for example, when the frequency f2 of the wobbling operation in the Y-axis direction is twice the frequency f1 of the wobbling operation in the X-axis direction, the wobbling operation in the Y-axis direction is executed as shown in FIG. During this time, the position of the laser beam in the X-axis direction within the incident surface 22a to the optical fiber 22 is held as shown in FIG. Therefore, the intensity of the laser beam does not change. Therefore, the position control of the laser beam in the Y-axis direction can be performed with high accuracy without being affected by the wobbling operation in the X-axis direction. As a result, the wobbling operation in the X-axis direction and the wobbling operation in the Y-axis direction can be performed simultaneously, and the wobbling operation can be speeded up.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be changed or improved as appropriate.

  For example, in each of the above-described embodiments, the laser light emitted from the optical fiber 21 is condensed toward the incident surface 22 a of the optical fiber 22 by the condenser lens 301. In addition, a concave mirror corresponding to the reflective optical element in the present invention may be used. Specifically, this will be described with reference to FIG. FIG. 12 is a schematic configuration diagram showing an embodiment of another example of the laser optical apparatus 1 according to the present invention. As shown in FIG. 12, the concave mirror is disposed on the optical axis of the laser light emitted from the optical fiber, and the condensing optical unit (not shown) centering on the point intersecting the optical axis of the laser light emitted from the optical fiber. And is fixed so that it can be moved. The laser light emitted from the optical fiber is reflected by the concave mirror, and is guided to one of the optical waveguides selected from the optical waveguides 1 to 3 to be condensed. Then, in the same manner as in the above-described embodiment, the condensing optical unit is rotated in the P and Q directions around the point where it intersects the concave mirror of the laser light via the actuator, and the laser light guided by the concave mirror is It is controlled so as to be directed toward the center in the incident plane. As a result, the position of the laser beam on the optical waveguide can be easily changed without complicating the apparatus.

1 is an overall configuration diagram of a laser optical device according to the present invention. It is a block diagram of the XY stage in the laser optical apparatus which concerns on this invention. It is a block diagram of the actuator in the laser optical apparatus which concerns on this invention. It is an electric circuit block block diagram in the laser optical apparatus which concerns on this invention. It is a schematic diagram which shows the drive circuit structure of the actuator in the laser optical apparatus which concerns on this invention. It is a time chart of the drive signal of the actuator in the laser optical apparatus concerning the present invention. It is a schematic diagram showing a wobbling operation in the laser optical device according to the present invention. It is a schematic diagram which shows the relationship between the laser profile and phase detection output in the laser optical apparatus which concerns on this invention. It is a flowchart which shows the flow of the wobbling operation | movement in the laser optical apparatus which concerns on this invention. It is a time chart of the wobbling operation | movement by an example in the laser optical apparatus based on this invention. It is a time chart of the wobbling operation | movement by another example in the laser optical apparatus based on this invention. It is a schematic block diagram by another example of the laser optical apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser optical apparatus 21, 22 Optical fiber 3 Condensing optical unit 301 Condensing lens 302 Lens holder 41, 42 Collimator lens 5 Half mirror 6 Photodiode (PD)
7 Controller 71 Low-pass filter (LPF)
72 Control CPU
721 A / D converter 723 Alignment controller 724, 725 X-PWM, Y-PWM
73 Driving circuit 731 732 X amplifier, Y amplifier 8, 9 Actuator (X axis, Y axis)
811 Piezoelectric element 812 Drive shaft 813 Weight 814 Moving body 10 Analog signal processing circuit

Claims (9)

A laser beam emitting section for emitting a laser beam;
A laser beam receiving unit that receives the laser beam emitted from the laser beam emitting unit;
A condensing optical unit for guiding the laser light emitted from the laser light emitting unit to the laser light receiving unit;
An actuator for moving the condensing optical unit;
An intensity detector for detecting the intensity of the laser beam introduced into the laser beam receiver;
A control unit that controls the operation of the actuator so that the laser beam guided by the condensing optical unit is directed to the center of the incident surface of the laser beam receiving unit based on the intensity of the laser beam detected by the intensity detecting unit. In a laser optical device having:
The actuator includes a piezoelectric element and a vibrating body that generates minute vibrations by excitation of the piezoelectric element and is in contact with the condensing optical unit so that a frictional force acts directly or indirectly. A laser optical device. The laser optical device according to claim 1, wherein the intensity of the laser beam detected by the intensity detection unit is acquired by the control unit while the actuator stops driving. The laser optical device according to claim 1, wherein the actuator is driven by a pulse signal from the control unit. The condensing optical unit includes a refractive optical element having power arranged on the optical axis of the laser light emitted from the laser light emitting unit,
4. The laser optical device according to claim 1, wherein the actuator moves the condensing optical unit along a plane substantially perpendicular to an optical axis of the laser light. 5. The condensing optical unit is arranged on the optical axis of the laser light emitted from the laser light emitting unit and focuses on the point intersecting with the optical axis of the laser light emitted from the laser light emitting unit. A reflective optical element having a power fixed to be slidable integrally with the optical unit;
4. The laser optical device according to claim 1, wherein the actuator swings the condensing optical unit around a point where the laser light intersects the reflective optical element. 5. The actuator includes a first wobbling operation in which the control unit periodically moves the condensing optical unit in a first movement direction at a predetermined frequency, and a second movement orthogonal to the first movement direction. 6. The laser optical apparatus according to claim 1, wherein a second wobbling operation that is periodically moved in a direction at a predetermined frequency is alternately performed. When the frequency of the first wobbling operation according to claim 6 is f1, and the frequency of the second wobbling operation is f2, f1 and f2 satisfy the following relationship (Equation 1) or (Equation 2):
The laser optical device according to claim 1, wherein the first wobbling operation and the second wobbling operation are simultaneously performed by the control unit in the actuator. .
f1 = 2 × n × f2 (Formula 1)
f2 = 2 × n × f1 (Formula 2)
(In the formula, n is a positive integer.) By moving the condensing optical unit that guides the laser beam to the laser beam receiving unit using the actuator, the laser beam emitted from the laser beam emitting unit is directed toward the center of the incident surface of the laser beam receiving unit. In a method for controlling the operation of an actuator,
The actuator includes a piezoelectric element and a vibrating body that generates minute vibrations by excitation of the piezoelectric element and is in contact with the condensing optical unit so that a frictional force acts directly or indirectly.
A detection step of detecting the intensity of the laser beam introduced into the laser beam receiving unit while the actuator is stopped driving;
Performing a first wobbling operation for periodically moving the condensing optical unit at a predetermined frequency in the first movement direction based on the intensity of the laser light detected in the detection step;
An operation of the actuator, wherein the actuator is alternately executed with a step of performing a second wobbling operation of periodically moving at a predetermined frequency in a second movement direction orthogonal to the first movement direction. How to control. When the frequency of the first wobbling operation according to claim 8 is f1, and the frequency of the second wobbling operation is f2, f1 and f2 satisfy the relationship of the following (Equation 1) or (Equation 2):
The method for controlling the operation of the actuator, comprising causing the actuator according to claim 8 to simultaneously execute the step of performing the first wobbling operation and the step of performing the second wobbling operation.
f1 = 2 × n × f2 (Formula 1)
f2 = 2 × n × f1 (Formula 2)
(In the formula, n is a positive integer.)

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